Simulations on Monitoring and Evaluation of Plasticity-Driven Material Damage Based on Second Harmonic of S₀ Mode Lamb Waves in Metallic Plates

Xiaoqiang Sun; Xuyang Liu; Yaolu Liu; Ning Hu; Youxuan Zhao; Xiangyan Ding; Shiwei Qin; Jianyu Zhang; Jun Zhang; Feng Liu; Shaoyun Fu

doi:10.3390/ma10070827

Simulations on Monitoring and Evaluation of Plasticity-Driven Material Damage Based on Second Harmonic of S₀ Mode Lamb Waves in Metallic Plates

Materials (Basel). 2017 Jul 19;10(7):827. doi: 10.3390/ma10070827.

Authors

Xiaoqiang Sun¹, Xuyang Liu², Yaolu Liu³, Ning Hu^{4

5}, Youxuan Zhao⁶, Xiangyan Ding⁷, Shiwei Qin⁸, Jianyu Zhang⁹, Jun Zhang¹⁰, Feng Liu¹¹, Shaoyun Fu¹²

Affiliations

¹ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. tiny_strong@sina.com.
² College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. liuxuyang@cqu.edu.cn.
³ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. liuyaolu@cqu.edu.cn.
⁴ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. ninghu@cqu.edu.cn.
⁵ Key Disciplines Lab of Novel Micro-Nano Devices and System and International R&D Center of Micro-Nano Systems and New Materials Technology, Chongqing University, Chongqing 400044, China. ninghu@cqu.edu.cn.
⁶ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. youxuan.zhao@cqu.edu.cn.
⁷ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. ddingxiangyan@yeah.net.
⁸ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. qsw123@163.com.
⁹ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. jyzhang@cqu.edu.cn.
¹⁰ College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. mejzhang@cqu.edu.cn.
¹¹ Department of Engineering Mechanics, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China. syfu@cqu.edu.cn.
¹² College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. liufengeaddr@126.com.

Abstract

In this study, a numerical approach-the discontinuous Meshless Local Petrov-Galerkin-Eshelby Method (MLPGEM)-was adopted to simulate and measure material plasticity in an Al 7075-T651 plate. The plate was modeled in two dimensions by assemblies of small particles that interact with each other through bonding stiffness. The material plasticity of the model loaded to produce different levels of strain is evaluated with the Lamb waves of S₀ mode. A tone burst at the center frequency of 200 kHz was used as excitation. Second-order nonlinear wave was extracted from the spectrogram of a signal receiving point. Tensile-driven plastic deformation and cumulative second harmonic generation of S₀ mode were observed in the simulation. Simulated measurement of the acoustic nonlinearity increased monotonically with the level of tensile-driven plastic strain captured by MLPGEM, whereas achieving this state by other numerical methods is comparatively more difficult. This result indicates that the second harmonics of S₀ mode can be employed to monitor and evaluate the material or structural early-stage damage induced by plasticity.

Keywords: evaluation; lamb waves; material plasticity; monitoring; second-order nonlinear wave.